RIB测井偏心影响效果的三维有限元模拟研究  

Three-Dimensional Finite Element Simulation of the Effect of Eccentricity in RIB Logging

作　　者：齐兴华 王祝文[1] 徐方慧 向旻 孟和 QI Xinghua;WANG Zhuwen;XU Fanghui;XIANG Min;MENG He(College of Geo-exploration Science and Technology, Jilin University, Changchun, Jilin 130026, China;College of Mining Engineering and Geology, Xinjiang Institute of Engineering, Urumqi, Xinjiang 834023, China;Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China)

机构地区：[1]吉林大学地球探测科学与技术学院,吉林长春130026 [2]新疆工程学院矿业工程与地质学院,新疆乌鲁木齐834023 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《测井技术》2022年第3期268-273,共6页Well Logging Technology

基　　金：国家自然科学基金项目“裂缝性火成岩储层的井孔声波传播规律及时频特征”(41874135);新疆自治区教育厅青年基金“地下水勘探专用高密度电法改进型仪器研发”(XJEDU2018Y051);新疆工程学院科研育人项目“固井水泥用量精准计算软件的研发”(2019XGY412112)。

摘　　要：八扇区水泥胶结(RIB)测井是一种通过声波幅度探测固井质量的测井方法。RIB测井采用沿井周分扇区探测的方式评价套管外不同区域内的固井质量,但因其源距较短导致测量结果受仪器偏心的影响较为严重。由于偏心程度对测量结果的影响难以量化,通过COMSOL Multiphysics软件以常见的5.5 in*套管为例对RIB测井在不同偏心程度下的测量结果进行三维有限元模拟。模拟结果表明:偏心方向一侧的扇区首波到达时间随偏心距离的增加而降低,而偏心反方向的扇区则不同程度地出现首波到达时间先升高再降低的现象。当套管外注满水泥时,各扇区对固井质量的评价不受偏心距离的影响。当套管外注满钻井液时,偏心距离大于4 mm会导致部分扇区的评价结果发生改变且随着偏心距离的增加而加剧,偏心距离超过8 mm会导致彻底误判。研究结果不仅证明RIB测井仪器需要严格居中,且对偏心结果的校正具有指导意义。RIB(Radial Incremental Bond)logging is a logging method to detect cementing quality through acoustic amplitude.Because it adopts the method of sector detection along the well circumference,it can evaluate the cementing quality in different areas outside the casing.But the measurement results are seriously affected by instrument eccentricity due to its short source distance.Since the influence of eccentricity on the measurement results is difficult to quantify,this paper uses COMSOL Multiphysics software to conduct a three-dimensional finite element simulation of the measurement results of RIB logging under different eccentricity levels with a common 5.5 inch casing as an example.The simulation results show that the arrival time of the first wave in the sectors on one side of the eccentricity direction decreases with the increase of the eccentricity distance,while the arrival time of the first wave increases and then decreases in the sectors on the opposite direction of the eccentricity.When the casing is filled with cement,the evaluation of cementing quality in each sector is not affected by the distance of ecentricity.When the casing is filled with drilling fluid,if the eccentricity distance is greater than 4 mm,the evaluation results of some sectors will change and intensify with the increase of eccentricity distance.If the eccentricity distance exceeds 8 mm,it will lead to complete misjudgment.The research results not only prove the strong demand of RIB logging for instrument centering,but also have obvious guiding significance for eccentric correction of RIB logging results.

关 键 词：水泥胶结 八扇区水泥胶结测井 有限元 COMSOL Multiphysics 偏心 

分 类 号：P631.84[天文地球—地质矿产勘探]